Paging is a well-defined and mature technology. Typically, short text messages are transmitted via radio signal from a transmitter at a central radio tower to a hand-held device for display. Recently this technology has been expanded to allow short text messages to be transmitted from a hand-held device back to the central radio receiver, then to be relayed to another user. Still, paging is not able to discern the position of any user. Cellular telephony offers another way of communication. There are efforts to discern the location of a mobile unit using reference signals at the base stations with limited success. The radio signals used for these types of communication can often be interrupted inside a building.
Global Positioning System (GPS) is gaining popularity using multiple signals transmitted from satellites in different locations in space to calculate the position of an electronic receiver. The cost and complexity of such device is high while service can often be interrupted inside a building. Moreover, any useful information associated with locality derived from longitude and latitude require costly and potentially vast amounts of data, which may not even be publicly available in some cases.
The concept of “ubiquitous computing,” pioneered by Xerox Palo Alto Research Center (www.parc.xerox.com), is generally intended to provide computing in an ubiquitous fashion Instead of carrying a computing device, the environment incorporates a computing facility to serve the user. Each user is given a self-identifying electronic device and the ‘computing’ facility uses this information to adjust various settings in the room to suit the individual and for other purposes, such as security. The concept requires a complete coverage and permanent association between the device and carrying individual.
There is also an increasing deployment of wireless ‘tags,’ such as for tolls collection, payment of gasoline purchase, etc. This technology identifies a tag within an area in order to charge a user's account. There is no tracking and no other communication utilities provided. Moreover, this application deals with one tag at a time.
To locate and to communicate with any person or object within a defined area/locale is an useful utility, especially for transient travelers, such as in a convention hall, shopping mall, amusement park, cruise ship, etc.
The present invention overcomes the aforementioned limitations with the following objects:
Low complexity and inexpensive mobile unit;
Pertinent local information;
Position tracking; and
Communication.
Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description thereof.